In a cone loudspeaker, the rearward end of the diaphragm is connected with the moving coil and, by way of a centering membrane, with the loudspeaker enclosure while its front end is connected with the loudspeaker enclosure by way of a bead. The centering membrane and the bead cause the diaphragm to be mobile as unimpededly as possible in the axial direction of the loudspeaker so as to produce the sound pressure but to be guided in the radial direction of the loudspeaker, i.e. to practically not move at all or as little as possible in this later direction. The diaphragm must here be connected with the bead along its forward circumferential edge.
The tone quality of a loudspeaker is here dependent, inter alia, on the proper functioning of the centering membrane and of the bead, as well as on the behavior of the diaphragm itself.